Method of fabricating clutch driven plate assembly



y 0, 1966 R. L. SMIRL 3,249,995

METHOD OF FABRICATING CLUTCH DRIVEN PLATE ASSEMBLY Original Filed Aug.11, 1961 2 Sheets-Sheet l flickardl.5mirl United States Patent 3,249,995METHOD OF FABRICATING CLUTCH DRIVEN PLATE ASSEMBLY Richard L. Smirl, LaGrange Park, IlL, assignor to Borg- Warner Corporation, Chicago, Ill., acorporation of Illinois Original application Aug. 11, 1961, Ser. No.130,906. Divided and this application Oct. 13, 1964, Ser. No.

1 Claim. (Cl. 29486) fabrication.

Heretofore, hub portions of driven plate assemblies for clutchmechanisms have been formed as forgings having a central sleeve withsplines for a driving connection to a driven shaft and having anintegral flange extending radially outwardly from the sleeve to whichwas bolted a flat annular hub plate. In some instances, the flange ofthe forging may have been formed sufficiently large so that the hubplate and sleeve were one piece. However, in each constructiontheforging method, although satisfactory, has not provided the reductionin assembly time and cost of fabrication apparent from this invention.Each forging would require all-over machining to adapt them for use,which, compared to the present method, is quite exorbitant. Furthermore,stronger materials may now be employed for construction of the hub plateand sleeve than have heretofore been possible by use of forgings.

Pursuant to these improvements, it is contemplated herein that the hubassembly be comprised of a flat circular hub plate having a centralportion adapted to extend radially inwardly to drivingly engage theoutput or driven shaft; the driving engagement is provided by having theopening in the central portion small enough so that its sides may besplined to the output shaft. Fused to marginal portions of the hub plateabout the opening are cylindrical sleeve members each having theircylindrical hollow interior in axial alignment with the plate opening.The fusion is accomplished by resistance welding producing a hub unitwherein the sleeve member and hub plate co-operate to distribute torqueloads to the output shaft. Splines are formed on the radially innersurface of the hub plate and each sleeve member following the weldingstep so that the splines may extend continuously through the fuscedpieces and be in perfect alignment.

It is a primary object an improved method of fabrication and resultingcon- .struction for a driven plate assembly used in a clutch mechanism.Among the intended advantages provided by the improved method are gainsin economy due to a reduction in assemblage time and a cost savingsresulting from use of standardized stock material components forconstructing various sized driven plate assemblies. Unnecessary all-overmachining operations are avoided. Use of simple stock material shapessuch as tubes and plate components permit the employment of moreductile, heat treated steels ordinarily prohibited by the forgingmethod.

Another object of this invention is to provide a driven plate assemblyfor a clutch having a more rugged hub plate cooperating with one or moresleeve members to transmit torque loads to an output shaft wherebyfailure of this invention to provide 3,249,995 Patented May 10, 1966 bylocalized stress is minimized. More particularly, this constructionprovides that a failure within the,hub will not make the vehicle withwhich it is used inoperative. The hub plate can transmit torque loads byitself should welding failures occur in the hub assembly.

Still another object of this invention is to provide an improved drivenplate assembly for a clutch whereby dampening means may be stationedmore closely adjacent the output shaft to provide a more compactassembly.

A still further object of this invention is to provide an improvedmethod of construction of a driven plate assembly for a clutch wherein acircular plate of substantially uniform thickness is formed with acentral opening adapted to engage the output shaft of said clutch,forming cylindrical sleeve members and integrally fusing said sleevemembers to the circular plate by resistance or projection welding, saidWelding step comprising the formation of annularly arranged projectionsalong one end of each sleeve and bringing said ends into' engagementwith the circular plate so that an electric current may be passedbetween the plate and sleeve members through said projections to producea fused and highly rigid, durable connection, and providing alignedsplines on the radially inner surfaces of the circular plate and sleevemembers.

The invention consists'of the novel constructions, arrangements anddevices to be hereinafter described and claimed for carrying out theabove-stated objects and such other objects as will appear from thefollowing description of a preferred form and alternative embodiments ofthe invention illustrated with reference to the accompanying drawings,wherein:

FIG. 1 is an elevational and central sectional view of a driven plateassembly embodying the features of this invention and illustrated asemployed in a typical fric tional clutch mechanism indicated in outline;

FIG. 2 is an enlarged fragmentary plan view of .the driven plateassembly taken substantially along line 2--2 of FIG. 1 and illustratingin dotted outline the Welding arrangement;

FIG. 3 is an enlarged fragmentary view of separated members of thedriven plate assembly illustrating one step in the construction of saidassembly;

FIG. 4 is an enlarged fragmentary view of a driven plate assemblyillustrating another embodiment of the invention; and

FIG. 5 is a fragmentary central sectional view of a drivenplate'assembly illustrating still another embodiment of this invention.

Turning now to the drawings and more particularly to FIGS. 1-3, there isillustrated a method of fabrication and resulting construction accordingto the present in vention.

The drawings are to be understood as being more or less of adiagram-matic'character for the purpose of disclosing preferred andalternative forms and the method of making the improved friction clutchdriven plate contemplated herein; in these drawings like referencecharacters identify the same or similar parts in different views. Thefrictional clutch mechanism in which the driven plate assembly isemployed may be briefly described as comprising generally an enginecrank shaft S carrying a rotatable driving member or flywheel F to whicha clutch pressure plate G is drivingly connected for axial move ment toeffect clutch engagement of a driven-plate assembly A which is carriedby the rotatable driven member or shaft D. The driven shaft D is pilotedas at P in the proximate end of driving crankshaft S. The clutch drivenplate assembly A has hub members drivingly connected to the driven shaftD. A clutch engaging force is normally applied by biasing means C actingbetween a provided having a hub plate, generally indicated 10,

formed as a single ply circular flat plate of substantially uniformthickness and having a central portion a with a central opening 11 (FIG.3) for receiving the driven shaft D and to be drivingly connectedthereto. The circular plate 10 may be made from hardened and ductilesteel materials or other type of metal adapted for a projection weldingoperation to be described hereinafter.

Next, a pair of sleeve members 12 are formed each having a central bore13 with an internal diameter generally commensurate with the diameter ofopening 11 of circular plate 10. At one end 14 of each of the sleevemembers (see FIG. 3), an annular ring projection 15 is formed extendingaxially outwardly from the annular face thereof. The ring projection 15may be formed with a generally triangular cross-section having the tip15a thereof as the outermost portion or extremity of the projection.

One sleeve member is then placed on each side of the circular plate 10in alignment with the opening 11 (FIG. 3). In such position, the ringprojection 15 should have its annular tip in engagement with the area ofthe circular plate marginal to opening 11 so as to place the constituentparts of the hub assembly in position for administering a projection orresistance welding operation.

While pressure is applied in an axial direction to the sleeve members tobring together and to force them toward the circular plate, anelectrical current is passed locally through the central portion of thecircular plate 10 so that it passes through the ring projection 15 andthence locally through the adjacent sleeve member. Such electricalcurrent may be applied to the plate and sleeve member from anyconvenient source and by suitable wiring connections (not shown). Uponapplication of the electrical current, the ring projection is'caused toact as a resistance element capable of building up a high internaltemperature resulting in a melting thereof. The metal of the circularplate 10 and sleeve member ends 14 surrounding the ring projection aresimilarly, but to a lesser degree, elevated in temperature by theelectrical current so as .to cooperate with the projection in providinga film of metal which integrally bonds the sleeve members and plate inan extremely strong manner. Destruction test results have shown suchbond to be of such strength that breakage in the driven plate assemblagewill occur first by the metal reaching its elastic limit before the weldsevers. Upon completion of resistance welding between the sleeve membersand the circular plate, the driven plate construction will appear asshown in FIG. 1, wherein the fiat annular face of end 14 of each sleevemember abuts the marginal area of the circular plate 10. In thisembodiment, the thickness of plate 10 is less than the thickness of thewalls of the sleeve members 12.

To adapt the driven plate for transmission of power to an output shaft,the sleeve members and circular plate, being in the rigidly connectedcondition, are provided with splines 16 on the internal surfaces whichdefine bores 13 and opening 11. The splines extend entirely through thewelded unit; splines on individual members of the unit are assured ofbeing in perfect alignment by virtue of forming the splines by a singletooling operation such as broaching.

To complete the driven plate assembly, the hub assembly is provided witha friction facing supporting assembly means L which preferably comprisesa plurality of yieldable spring cushion members 25 which extend radiallyalong side the plate 10 and have an inner region fastened to plate 10 bysuitable rivets 22 extending through circumferentially spaced andaligned openings 23 and 24 in the plate 10 and cushion members 25respectively. Axially spaced annular friction facings 27 are anchored toopposite sides of the cushions by rivets 28, whereby said cushionsnormally space the facings yieldably from each other so that under thepressure which is exerted during clutch engagement said cushions areadapted to collapse against the confronting surfaces of the frictionfacings.

Such method of construction provides several advantages, among which isthe ability of the driven plate assembly to unload torque applied to thefriction facing assembly L in a gradual manner to shift such loads tothe hub plate 10 when weakening of the weld, although unlikely, occursbetween it and the sleeve members. The weld is always prevented fromgoing to a complete separation by virtue of such shifting.

As shown in FIGS. 4 and 5, an alternative embodiment is illustrated,having parts similar to those of the preferred embodiment prefixed by 1,and having a construction in which a central portion 111 of a circularhub plate is formed with an annular axially extending flange protrudingfrom one side thereof. The flange 130 has a central opening 111a adaptedto be drivingly connected to a driven shaft (not shown). This embodimentemploys only one sleeve member 112 formed with an annular shoulder 131at end 114 thereof. The shoulder 131 has formed thereon a continuousannular ring 132 with a triangular cross-section similar to thecross-section of ring projection 15 of the preferred embodiment. Theouter annular lip of ring 132 is placed in engagement with the annularshoulder 134 of flange 130 when the bore 113 of the sleeve member isaligned with the opening 111a of the flange. This positioning preparesthe plate and sleeve member for accomplishing the welding step inaccordance with the steps described for the preferred embodiment; theremaining steps are also similar wherein splines are formed in the wallsof the bore 113 and opening 111a and the friction facing assembly isapplied to the outer region of plate 110.

Still another embodiment is illustrated in FIG. 5 wherein parts similarto those of the preferred embodiment are prefixed by 2; thisconstruction employs a vibration dampening assembly V between thefriction-facing assembly and the'hub plate assembly H. The hub plateassembly comprises a metal hub plate 210 formed as a circular flatmember of substantially uniform thickness having a central portion 211with an opening 211a and having a' plurality of apertures locatedpreferably radially inwardly from the outer periphery of the plate 210for receiving elements of the vibration dampener assembly. A sheet metaldisc 241 is carried on the hub assembly H and is adapted to support thefriction facing assembly at its outer region. The disc 241 has a centralopening 242 adapted to be spaced from a sleeve member periphery, to bedescribed. The disc 241 extends radially along side and spaced from theadjacent forward face 211b of the hub plate 210.

An annular sheet metal washer plate 243 is positioned next to the hubplate 210 on the side thereof which is opposite the disc 241. Theoutside diameter of said washer plate is approximately the same as theouter diameter of said hub plate 210 with which it is associated and hasa central opening 243a with a diameter generally commensurate with thediameter of opening 242. Spool rivets 244 tie together the outer regionof washer plate 243 and the adjacent region of disc 241 in a manner forconjoint rotation. The enlarged body portions of these rivets 244 passloosely through notches 245 in the rim of the hub plate 210. All ofthese notches are greater in circumferential dimensions than thediameter of the bodies of the spool rivets 244, thereby permittinglimited rotative movement of said disc and washer plate relative to thehub plate 210.

A circumferentially extending row of openings 246 is made both in thedisc and washer plate in registry with the apertures 240 of the hubplate. A pluralitay of coil springs 247 are seated in the apertures andopenings 240 and 246 to resiliently and drivingly connect the disc, thehub plate and washer plate in a manner so that these parts are adaptedto rotate in unison. Frictional braking means 248 are provided forco-operation with hub plate, disc and washer plate during relativerotative movement between these parts. The braking means may preferablytake the form of friction washers or spacers of thin metal.

The effect of the. yieldable vibration dampener assembly, including thebraking means, is to dampen vibrations and rattle which may occur duringreversal of torque or acceleration of driving speed in the operation ofthe device with which the clutch mechanism is used, while the drivenplate assembly is clamped between the pressure means and flywheel of theclutch.

To provide the hub assembly of this embodiment with a driving connectionwith the driven shaft D, the hub plate 210 has its central portion 211adapted to engage the shaft D. The walls of central openings 243a and242 ofv Washer plate 243 and disc 241respectively are spaced slightlyoutwardly from cylindrical sleeve members 212, integrally bonded torespectively opposite sides of the hub plate; the bore of each sleevemember is generally aligned with the central opening of the hub plate.Each sleeve member is fused to hub plate 210 at its end 214 in themanner previously described by use of an annular ring to accomplish aresistance weld therebetween.

In the embodiment of FIG. 5, it should be pointed out that the method ofconstruction of this invention enables the dampening means to be spacedmore closely to the driven shaft than known constructions, therebyproviding a more compact clutch unit commensurate with aims of modernautomobile design.

The thickness of the hub plate 210 is generally commensurate with thethickness of the sleeve member walls and is generally greater inthickness than the plate of FIG. 1. In effect, the hub plate 210 isadapted to carry full torque loads, if necessary, through its ownsplines to the driven shaft and thereby make the driven plate assemblyindependent of strength of the bond between the sleeve members and hubplate.

It is to be understood that the invention is not to be limited to thespecific constructions and arrangements shown and described, except onlyinsofar as the claim may be so limited, as it will be understood tothose skilled in the art that changes may be made without departing fromthe principals of the invention.

I claim:

In a clutch assembly, a method for constructing a driven plate assembly,comprising the following steps: forming a circular flat sheet metalplate of generally uniform thickness with a central opening defined byan inner peripheral wall extending therethrough; forming two straightcylindrical tubes, each having a wall with a uniform thickness andhaving a central bore extending therethrough of substantially the samediameter as the diameter of said opening, one end of each said tubebeing formed with a tapered annular projection extending axiallyoutwardly therefrom; placing each said tube adjacent said plate with thebore and opening in general alignment and with the extremity of saidprojection in engagement with the margin of said plate about saidopening; passing an electric current simultaneously between each saidtube and plate through said annular projections while applying pressureto said tubes and plate causing them to move axially together, saidelectric current being suflicient to melt said projections and adjacentplate and tube surfaces to fuse said plate and tubes together; formingsplines along the walls of said openings and bore which extends inalignment through both plate and tubes; and providing a friction facingassembly means for connections to the outer regions of said plate.

References Cited by the Examiner UNITED STATES PATENTS 877,398 1/1908 IBrinley 21993 XR 904,540 11/1908 Lachman 21993 1,982,235 11/1934 Shepard192-107 2,006,458 7/1935 Jones et a1. 21993 2,247,690 1/ 1941 Nutt.2,506,641 5/1950 Hoover 74449 2,870,707 1/ 1959 Lyon 29-481 XR 2,932,8844/1960 Lyon 29-481 XR 2,968,713 4/1961 Harper 21993 WHITMORE A. WILTZ,Primary Examiner.

JOHN F. CAMPBELL, P. M. COHEN, Examiners.

